DOCSLIB.ORG

The Case for a Gaian Bottleneck: the Biology of Habitability

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Case for a Gaian Bottleneck: the Biology of Habitability See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/291334824 The Case for a Gaian Bottleneck: The Biology of Habitability Article in Astrobiology · January 2016 DOI: 10.1089/ast.2015.1387 CITATIONS READS 33 1,009 2 authors: Aditya Chopra Charley Lineweaver Australian National University Australian National University 13 PUBLICATIONS 109 CITATIONS 198 PUBLICATIONS 7,652 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Entropy View project Atavistic model of cancer View project All content following this page was uploaded by Charley Lineweaver on 25 January 2016. The user has requested enhancement of the downloaded file. ASTROBIOLOGY Volume 16, Number 1, 2016 ª Mary Ann Liebert, Inc. DOI: 10.1089/ast.2015.1387 The Case for a Gaian Bottleneck: The Biology of Habitability Aditya Chopra and Charles H. Lineweaver Abstract The prerequisites and ingredients for life seem to be abundantly available in the Universe. However, the Universe does not seem to be teeming with life. The most common explanation for this is a low probability for the emergence of life (an emergence bottleneck), notionally due to the intricacies of the molecular recipe. Here, we present an alternative Gaian bottleneck explanation: If life emerges on a planet, it only rarely evolves quickly enough to regulate greenhouse gases and albedo, thereby maintaining surface temperatures compatible with liquid water and habitability. Such a Gaian bottleneck suggests that (i) extinction is the cosmic default for most life that has ever emerged on the surfaces of wet rocky planets in the Universe and (ii) rocky planets need to be inhabited to remain habitable. In the Gaian bottleneck model, the maintenance of planetary habitability is a property more associated with an unusually rapid evolution of biological regulation of surface volatiles than with the luminosity and distance to the host star. Key Words: Life—Habitability—Gaia—Abiogenesis habitable zone (AHZ)—Circumstellar habitable zone (CHZ). Astrobiology 16, 7–22. 1. Fermi’s Paradox, Hanson’s Great Filter, our galaxy is because life’s emergence is difficult and rare. In and Bostrom’s Bottlenecks this case, humanity has already survived the biggest threat to its continued existence; the biggest bottleneck is behind us, e see no evidence that our galaxy has been colonized and we can relax. However, if we find life on Mars that has Wby an advanced technological civilization. Archae- evolved independently of life on Earth, this would be strong ological excavations have not unearthed alien spaceships, and evidence that there is no emergence bottleneck. If we find the optical and radio searches for extraterrestrial intelligence such life, Bostrom argues that the biggest bottleneck—the have not been successful (Tarter, 2001). If one assumes that self-destruction bottleneck—would then be in front of us. This once life emerges it evolves toward intelligence and techno- would be ‘‘by far the worst news ever printed on a newspaper logical civilizations, we are faced with Fermi’s paradox: cover.’’ As a plausible alternative to such catastrophic logic, Where is everybody? [Webb (2002), C´ irkovic´ (2009); but also we introduce the concept of a Gaian bottleneck, a bottleneck see Gray (2015) and Ward and Brownlee’s (2000) Rare Earth that life on Earth has already passed through. If such a bot- hypothesis]. To put this information in context, Hanson (1998) tleneck exists, the discovery of extant independently evolved introduced the concept of a Great Filter, describing the pos- martian life might be bad news, but the discovery of extinct sible bottlenecks in the assumed progression from molecular independently evolved martian life would not be. chemistry to life, from life to intelligence, and from intelli- In the standard view, the decrease in bombardment rate from gence to galactic colonization. If the emergence of life is a rare *4.5 to *3.8 Gya is associated with making Earth more and difficult process, then an emergence bottleneck could re- clement and thus enabling life to emerge and persist (Maher solve Fermi’s paradox. However, if technological civilizations and Stevenson, 1988). In contrast to this view, we postulate a inevitably destroy themselves, this self-destruction bottleneck Gaian bottleneck model in which early life (on Earth and could also resolve Fermi’s paradox. elsewhere) is not just a passive passenger but comes under Bostrom (2008) argued that the Great Filter is a valuable strong selection pressure to actively modify and regulate its tool for assessing existential risks to humanity. If the biggest environment. The emergence of life’s abilities to modify its barrier in the Great Filter is the emergence bottleneck, then environment and regulate initially abiotic feedback mecha- we will find no independently evolved life on Mars, and the nisms (what we call Gaian regulation) could be the most sig- apparent absence of advanced technological civilizations in nificant factor responsible for life’s persistence on Earth. Planetary Science Institute, Research School of Earth Sciences, Research School of Astronomy and Astrophysics, The Australian National University, Canberra, Australia. 7 8 CHOPRA AND LINEWEAVER This highlights an important difference between physics- observations suggest that this sequence—the formation of based estimates of habitability and the more unpredictable terrestrial planets—is not a rare occurrence that needs special patterns of biological evolution on the highly unstable sur- initial conditions. There seems to be no rocky-planet-in-the- face environments of young terrestrial planets. For example, CHZ bottleneck responsible for reducing the probability for bombardment rates inevitably decrease in the circumstellar the emergence of life. habitable zones (CHZs) of stars, but the timescales for the evolution of Gaian regulation are probably unpredictable 2.2. No elemental or molecular ingredient bottleneck. and would not inevitably evolve rapidly (or at all). Thus, if Life on Earth is made of hydrogen, oxygen, carbon, ni- there is anything special about what happened on Earth to trogen, sulfur, and phosphorus: ‘‘HOCNSP’’ (Chopra et al., allow life to persist here, it might have less to do with the 2010). HOCNSP are among the most abundant atoms in the decreasing bombardment rate in the Hadean, or special Universe (Pace, 2001; Lodders et al., 2009; Lineweaver and chemical ingredients, or sources of free energy, or even a Chopra, 2012b). Since the elemental ingredients for life are rare recipe for the emergence of life. The existence of life on the most common elements in the Universe, it is not surprising Earth today might have more to do with the unusually rapid that the molecular ingredients of life are also common. biological evolution of effective niche construction and Of the elements in the Universe that form molecules, water Gaian regulation in the first billion years. Habitability and (H O) is the combination of the first and second most abun- habitable zones would then not only be a passive abiotic 2 dant elements. Water should be a common feature of rocky property of stellar and planetary physics and chemistry planets (Raymond et al., 2004, 2007; Elkins-Tanton, 2012). (such as stellar luminosity, initial water content, and de- Radial mixing during the epoch of oligarchic growth ensures creasing bombardment rate) but would also be a result of that some water-rich materials from beyond the snowline are early life’s ability to influence initially abiotic geochemical injected into the more water-poor material of the feeding cycles and turn them into the life-mediated biogeochemical zones of rocky planets in the CHZ. Thus, it is likely that Mars cycles that we are familiar with on the current Earth (Len- and Venus both started out, like Earth, hot from accretional ton, 1998; Lenton et al., 2004; Schneider, 2004; Falkowski energy and impacts and wet from impacts of large hydrous (5– et al., 2008; Kump et al., 2009). Without rapid evolution of 20% water) asteroids from the outer asteroid belt (Morbidelli Gaian regulation, early extinction would be the most com- et al., 2000, 2012) and other ‘‘wet’’ accretionary material mon fate of planetary life. Even if the emergence of life is a (Drake and Righter, 2002; Drake, 2005). Terrestrial planets in common feature of wet rocky planets throughout the Uni- other planetary systems are also likely to start with variable, verse, the Gaian bottleneck model suggests that inhabited non-negligible amounts of water. Earth-like planets would be rare. Current terrestrial life is built of monomers such as amino acids, fatty acids, sugars, and nitrogenous bases. Amino acids 2. If There Is an Emergence Bottleneck, link together to form proteins; fatty acids link to form lipids; It Is Probably ‘‘Recipe-Based’’ sugars link to form carbohydrates; and nitrogenous bases 2.1. No stellar bottleneck. No wet-rocky-planet combine with sugar and phosphate to make nucleotide mono- bottleneck. Sun-like stars and Earth-like mers, which link to form RNA/DNA (Lineweaver and Chopra, planets are common. 2012b). Thus, life on Earth emerged when available monomers linked together to make polymers. Amino acids and other or- If our Sun were the most uranium-rich star in the Galaxy, ganic monomers fall from the skies in carbonaceous chondrites. and if life on Earth were uranium-based (instead of carbon- We have no reason to believe that the availability of these based), then we would have good reason to believe that life monomers is somehow unique to Earth or the Solar System. (either its emergence or persistence, or both) requires a rare The flux of such organics was particularly high during the first kind of uranium-rich host star. However, we have been billion years of the formation of Earth, and we have no reason to unable to identify any significant differences between the believe that this will not be the case during the formation of Sun and other stars that could plausibly be connected with terrestrial planets in other planetary systems.
Load more

Recommended publications
  • Lecture-29 (PDF)
    Life in the Universe Orin Harris and Greg Anderson Department of Physics & Astronomy Northeastern Illinois University Spring 2021 c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 1 / 95 Overview Dating Rocks Life on Earth How Did Life Arise? Life in the Solar System Life Around Other Stars Interstellar Travel SETI Review c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 2 / 95 Dating Rocks Zircon Dating Sedimentary Grand Canyon Life on Earth How Did Life Arise? Life in the Solar System Life Around Dating Rocks Other Stars Interstellar Travel SETI Review c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 3 / 95 Zircon Dating Zircon, (ZrSiO4), minerals incorporate trace amounts of uranium but reject lead. Naturally occuring uranium: • U-238: 99.27% • U-235: 0.72% Decay chains: • 238U −→ 206Pb, τ =4.47 Gyrs. • 235U −→ 207Pb, τ = 704 Myrs. 1956, Clair Camron Patterson dated the Canyon Diablo meteorite: τ =4.55 Gyrs. c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 4 / 95 Dating Sedimentary Rocks • Relative ages: Deeper layers were deposited earlier • Absolute ages: Decay of radioactive isotopes old (deposited last) oldest (depositedolder first) c 2012-2021 G. Anderson., O. Harris Universe: Past, Present & Future – slide 5 / 95 Grand Canyon: Earth History from 200 million - 2 billion yrs ago. Dating Rocks Life on Earth Earth History Timeline Late Heavy Bombardment Hadean Shark Bay Stromatolites Cyanobacteria Q: Earliest Fossils? Life on Earth O2 History Q: Life on Earth How Did Life Arise? Life in the Solar System Life Around Other Stars Interstellar Travel SETI Review c 2012-2021 G.
    [Show full text]
  • A Theoretical Astro-Biological Solution for Femi's Paradox
    2019 International Conference on Social Science, Economics and Management Research (SSEMR 2019) ISBN: 978-1-60595-638-1 A Theoretical Astro-biological Solution for Femi’s Paradox Xiang-rui LUO* and Wei WANG University of North Carolina at Chapel Hill, NC, USA Guiyang University, Guizhou, China *Corresponding author Keywords: Astrophysics, Femi’s paradox, Extraterrestrial civilizations. Abstract. The Great Filter Theory is a commonly accepted solution for Fermi’s Paradox, indicating that there is a huge wall preventing the intelligent species from achieving Level III Civilization, Galactic Civilization, which has the ability to control the energy on the scale its entire galaxy. There are many forms of hypothesis about what the Great Filter is, such as unbreakable light speed limit. Here we analyze the hypothesis that the Great Filter is the irreconcilable predicament between advanced technology and limited lifespan, which inevitably leads to stagnation in technology development. Introduction The Fermi paradox, or Fermi's paradox is the apparent contradiction between the lack of evidence and high probability estimates for the existence of extraterrestrial civilizations. The basic reasoning line, made by physicists Enrico Fermi (1901–1954) and Michael H. Hart (born 1932), are: There are at least 100 billion planets in our Galaxy alone (Cassan et al. 2012), and about 20% are of habitable zone (Petigura et al. 2013). With high probability, some of these stars have Earth-like planets, and if the Earth is typical, some may have developed intelligent life. Some of these civilizations may have developed interstellar travel, a step the Earth is investigating now. Even at the slow pace of currently envisioned interstellar travel, the Milky Way galaxy could be completely traversed in a few million years.
    [Show full text]
  • Where Are They? Why I Hope the Search for Extraterrestrial Life Finds Nothing
    Close Window May/June 2008 Where Are They? Why I hope the search for extraterrestrial life finds nothing. By Nick Bostrom People got very excited in 2004 when NASA's rover Opportunity discovered evidence that Mars had once been wet. Where there is water, there may be life. After more than 40 years of human exploration, culminating in the ongoing Mars Exploration Rover mission, scientists are planning still more missions to study the planet. The Phoenix, an interagency scientific probe led by the Lunar and Planetary Laboratory at the University of Arizona, is scheduled to land in late May on Mars's frigid northern arctic, where it will search for soils and ice that might be suitable for microbial life (see "Mission to Mars," November/December 2007). The next decade might see a Mars Sample Return mission, which would use robotic systems to collect samples of Martian rocks, soils, and atmosphere and return them to Earth. We could then analyze the samples to see if they contain any traces of life, whether extinct or still active. Such a discovery would be of tremendous scientific significance. What could be more fascinating than discovering life that had evolved entirely independently of life here on Earth? Many people would also find it heartening to learn that we are not entirely alone in this vast, cold cosmos. But I hope that our Mars probes discover nothing. It would be good news if we find Mars to be sterile. Dead rocks and lifeless sands would lift my spirit. Conversely, if we discovered traces of some simple, extinct life-form--some bacteria, some algae--it would be bad news.
    [Show full text]
  • Could Affect Tech Advances in Space 14 May 2014, by Elizabeth Howell
    How the 'Great Filter' could affect tech advances in space 14 May 2014, by Elizabeth Howell That's an important part of the Great Filter, but more details about it are below. Here are a few possibilities for why the filter exists, both from Snyder-Beattie and from the person who first named the Great Filter, Robin Hanson, in 1996. 'Rare Earth' hypothesis Maybe Earth is alone in the universe. While some might assume life must be relatively common since it arose here, Snyder-Beattie points to observation selection effects as complicating this analysis. With Kepler-62f, an exoplanet that is about 40% larger than a sample size of one (only ourselves as the Earth. It’s located about 1,200 light-years from our solar observers), it is hard to determine the probability of system in the constellation Lyra. Credit: life arising – we could very well be alone. By one NASA/Ames/JPL-Caltech token, that's a "comforting" thought, he added, because it could mean there is no single catastrophic event that befalls all civilizations. "One of the main things we're focused on is the Advanced civilizations are hard to get notion of existential risk, getting a sense of what the probability of human extinction is," said Andrew Hanson doesn't believe that one. One step would Snyder-Beattie, who recently wrote a piece on the be going from modestly intelligent mammals to "Great Filter" for Ars Technica. human-like abilities, and another would be the step from human-like abilities to advanced civilizations. As Snyder-Beattie explained in the article, the It only took a few million years to go from modestly "Great Filter" is a response to the question of why intelligent animals to humans.
    [Show full text]
  • Galactic Gradients, Postbiological Evolution and the Apparent Failure of SETI Milan M
    Galactic Gradients, Postbiological Evolution and the Apparent Failure of SETI Milan M. Cirkovi´´ c Astronomical Observatory Belgrade, Volgina 7, 11160 Belgrade-74, Serbia and Montenegro E-mail: [email protected] Robert J. Bradbury Aeiveos Corporation PO Box 31877 Seattle, WA 98103, USA E-mail: [email protected] Abstract Motivated by recent developments impacting our view of Fermi’s para- dox (the absence of extraterrestrials and their manifestations from our past light cone), we suggest a reassessment of the problem itself, as well as of strategies employed by SETI projects so far. The need for such reassessment is fueled not only by the failure of SETI thus far, but also by great advances recently made in astrophysics, astro- biology, computer science and future studies. Therefore, we consider the effects of the observed metallicity and temperature gradients in the Milky Way on the spatial distribution of hypothetical advanced extraterrestrial intelligent communities. While properties of such com- munities and their sociological and technological preferences are, ob- viously, entirely unknown, we assume that (1) they operate in agree- ment with the known laws of physics, and (2) that at some point they typically become motivated by a meta-principle embodying the central role of information-processing; a prototype of the latter is the recently suggested Intelligence Principle of Steven J. Dick. There are specific conclusions of practical interest to astrobiological and SETI endeavors to be drawn from coupling of these reasonable assumptions with the astrophysical and astrochemical structure of the spiral disk of our Galaxy. In particular, we suggest that the outer regions of the Galactic disk are most likely locations for advanced SETI targets, and that sophisticated intelligent communities will tend to migrate out- ward through the Galaxy as their capacities of information-processing increase, for both thermodynamical and astrochemical reasons.
    [Show full text]
  • Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets, and the New Search for Life Beyond Our Solar System
    Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets, and the New Search for Life beyond Our Solar System By Michael E. Summers and James Trefil Smithsonian Books (14 March 2017) ISBN-10: 1588345947 ISBN-13: 978-1588345943 “We labor under what we call ‘the curse of the single example’ – that is how the authors Michael E. Summers and James Trefil introduce the first chapter “not your Grandfathers Galaxy”. Almost to the day, sixty years after the then called Soviet Union sent the first man made satellite (“Sputnik”) into low Earth orbit, the authors summarize the findings and answers to age-old fundamental questions which humankind was enabled by this event – by having driven space exploration to unbelievable heights never before thought possible. Definition of exoplanets The initial idea for a habitable exoplanet was the “Goldilocks” model: a hypothetical body similar to Earth situated in a position near its star that makes it ”not too hot, not too cold, but just right”, just right meaning it can have oceans of liquid water on its surface i.e., in what has been termed the continuously habitable zone (CHZ). The notion of planetary systems circling other stars was confirmed in 1992, however that discovery was a surprise – the planets were found to be circling the wrong kind of star, a pulsar, i.e., a star at the end of its life. The next surprise, using the measurements from the Kepler spacecraft, was a diverse assortment of exoplanets such as Super Earths (rocky planets), Styrofoam worlds (planets so light it is difficult to explain how they have not collapsed under their own gravity), Diamond planets made of almost pure carbon, Multi star worlds (planets that circle up to four stars), Hot Earths (so close to their stars that their surface rocks are vaporized) and Rogue planets wandering around unattached to stars.
    [Show full text]
  • A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy
    galaxies Article A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy Xiang Cai 1, Jonathan H. Jiang 2,*, Kristen A. Fahy 2 and Yuk L. Yung 3 1 Grade 12, Santiago High School, Corona, CA 92881, USA; [email protected] 2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; [email protected] 3 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA; [email protected] * Correspondence: [email protected] Abstract: In the field of astrobiology, the precise location, prevalence, and age of potential extrater- restrial intelligence (ETI) have not been explicitly explored. Here, we address these inquiries using an empirical galactic simulation model to analyze the spatial–temporal variations and the prevalence of potential ETI within the Galaxy. This model estimates the occurrence of ETI, providing guidance on where to look for intelligent life in the Search for ETI (SETI) with a set of criteria, including well-established astrophysical properties of the Milky Way. Further, typically overlooked factors such as the process of abiogenesis, different evolutionary timescales, and potential self-annihilation are incorporated to explore the growth propensity of ETI. We examine three major parameters: (1) the likelihood rate of abiogenesis (λA); (2) evolutionary timescales (Tevo); and (3) probability of self- annihilation of complex life (Pann). We found Pann to be the most influential parameter determining the quantity and age of galactic intelligent life. Our model simulation also identified a peak location for ETI at an annular region approximately 4 kpc from the galactic center around 8 billion years (Gyrs), with complex life decreasing temporally and spatially from the peak point, asserting a high Citation: Cai, X.; Jiang, J.H.; Fahy, likelihood of intelligent life in the galactic inner disk.
    [Show full text]
  • The Search for Habitable Worlds in Our Galaxy
    THE SEARCH FOR HABITABLE WORLDS IN OUR GALAXY RAVI KOPPARAPU NASA GODDARD RADIAL VELOCITY TECHNIQUE Courtesy: ESO Large mass, short period planets are easier to detect. TRANSIT DETECTION https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11428 TRANSIT SPECTROSCOPY KEPLER MISSION DIRECT IMAGING MISSION STUDIES From Kepler mission From Kepler mission STELLAR SPECTRAL TYPES F: ~7000K - 6000K (~2 Gyr) G: ~6000K - 5000K (~10 Gyr) K: ~5000K - 4000K (~30 Gyr) M: ~4000K - 2600K (~100 Gyr) Circumstellar region where a terrestrial size/mass planet with a “suitable” atmosphere can maintain liquid-water on it’s surface. This definition of HZ has little to do with habitability. It is a subset of a larger definition of “The” habitable zone where life can arise (irrespective of detectability) REQUIREMENT OF SURFACE LIQUID WATER Life on Earth requires liquid water during its life cycle. So,our first choice is to look for other planets like Earth It is unlikely that a subsurface biota could modify a planetary atmosphere in a way that could be observed remotely WHY “LIQUID WATER”? Oxygen Hydrogen Hydrogen Water is a “polar” molecule. And a universal solvent! Can form bonds allowing chemical reactions. “WATER ON THE SURFACE OF A PLANET”? Oxygen Methane Green plants and algae (and cyanobacteria) produce oxgyen from photosynthesis. Bacteria produce methane. A combination of these two gases could be a potential life signature. Currently, we can only see the outer atmospheres of planets remotely, using telescopes. So, we look for signatures that affect a planet’s atmosphere. HYDROGEN HABITABLE ZONES “Habitability doesn’t mean much if there is no star” 1-D climate model assuming an Earth-like planet with H2O dominated atmospheres at the inner edge, and CO2 dominated atmospheres at the outer edge (N2 background gas) Kasting, Whitmire & Reynolds (1993) WHAT ARE THE HZS AND WHERE ARE THEY? Inner edge Moist greenhouse: The ocean remains liquid, but the stratosphere becomes wet, leading to rapid photodissociation of water and escape of hydrogen to space.
    [Show full text]
  • ASTR1000 Lecture (Meisel, Spring 2021)
    An introduction to the Drake Equation Zach Meisel Ohio University - ASTR1000 How many intelligent, communicating extraterrestrial civilizations are out there? • The Drake Equation is a tool to approach this question in a semi-quantitative way • The number of civilizations that we could communicate with ( ) is determined by the rate of star formation ( ), the fraction of those stars with planets ( ), the number those planets for a given star that are habitable ( ), the fraction of those habitable planets that develop life ( ), the fraction of those life-developing planets that result in intelligent life ( ), the fraction of civilizations that develop the ability to communicate over long distances ( ), and the lifetime of that civilization ( ) • Putting it all together: = readily (much) more quantifiablespeculative in = • The rate of star formation can be calculated by considering the mass of stars in the Milky Way, an initial mass function, and stellar lifetimes to arrive at something like ~4 stars/year Licquia & Newman ApJ 2015 JohannesBuchner in = •The fraction of stars with planets is thought to be ~1, taking into account the sensitivity of exoplanet detection methods and assuming a planetary mass function Cassan et al. Nature 2012 in = • The number of habitable planets per planet-hosting star is based on the criterion adopted for habitability (e.g. atmosphere conditions, moons, methane-based life, light flux, temperature) • Using a (likely) rocky surface and (likely) ability to sustain liquid water, ~60 of the ~4,600 exoplanets detected to date are considered potentially habitable. Adding moons into the picture (see Intro to Solar System Life) probably doubles this number • So ~0.02 isn’t unreasonable, though detection bias & expanding criteria for habitability could make this ~1 Kopparapu et al.
    [Show full text]
  • Viewing the Technosphere in an Interplanetary Light Bronislaw
    To appear in The Anthropocene Review. Author final version, July 2016. Viewing the technosphere in an interplanetary light Bronislaw Szerszynski (Lancaster University, UK) [email protected] Abstract In this paper I argue that discussion about the ‘technosphere’ as an emergent new Earth system needs to be situated within wider reflection about how technospheres might arise on other worlds. Engaging with astrobiological speculation about ‘exo-technospheres’ can help us to understand whether technospheres are likely, what their preconditions might be, and whether they endure. Engaging with science fiction can help us to avoid observer biases that encourage linear assumptions about the preconditions and emergence of technospheres. Exploring earlier major transitions in Earth’s evolution can shed light on the shifting distribution of metabolic and reproductive powers between the human and technological parts of the contemporary technosphere. The long-term evolution of technical objects also suggests that they have shown a tendency to pass through their own major transitions in their relation to animality. Such reflection can shed new light on the nature and likely future development of the Earth’s technosphere. Keywords technosphere, Anthropocene, astrobiology, macroevolution, history of technology, science fiction In an important series of papers, Peter Haff (2010; 2014a; 2014b; 2014c) has proposed a new way of looking at technology, one which treats it, along with human beings and their institutions, as parts of an emergent component of the Earth system, the ‘technosphere’, which he suggests is a crucial defining feature of the proposed new geological epoch the ‘Anthropocene’. For Haff, the technosphere includes all large-scale interconnected technological systems such as those involved in energy, transportation and agriculture, the devices, human beings and institutions directly and indirectly involved in their operation, and the built environment that sustains and supports all of these (Haff, 2014a: 127).
    [Show full text]
  • Fermi Paradox from Wikipedia, the Free Encyclopedia Jump To: Navigation, Search
    Fermi paradox From Wikipedia, the free encyclopedia Jump to: navigation, search This article is about the absence of evidence for extraterrestrial intelligence. For the type of estimation problem, see Fermi problem. For the music album, see Fermi Paradox (album). For the short story, see The Fermi Paradox Is Our Business Model. A graphical representation of the Arecibo message – Humanity's first attempt to use radio waves to actively communicate its existence to alien civilizations The Fermi paradox (or Fermi's paradox) is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilization and humanity's lack of contact with, or evidence for, such civilizations.[1] The basic points of the argument, made by physicists Enrico Fermi and Michael H. Hart, are: • The Sun is a young star. There are billions of stars in the galaxy that are billions of years older; • Some of these stars likely have Earth-like planets[2] which, if the Earth is typical, may develop intelligent life; • Presumably some of these civilizations will develop interstellar travel, as Earth seems likely to do; • At any practical pace of interstellar travel, the galaxy can be completely colonized in just a few tens of millions of years. According to this line of thinking, the Earth should have already been colonized, or at least visited. But no convincing evidence of this exists. Furthermore, no confirmed signs of intelligence elsewhere have been spotted, either in our galaxy or the more than 80 billion other galaxies of the
    [Show full text]
  • The Arrival of the Great Filter and the Fermi Paradox
    THE ARRIVAL OF THE GREAT FILTER AND THE FERMI PARADOX DANIELE ZAMORI ABSTRACT: The purpose of this paper is to seek an explanation to the following questions: “What is the Great Filter?” and “When it will arrive?”. Creating a theoretical model capable to provide an objectively valuable solution over those issues, it is also possible to hypothesize a valid solution for the Fermi paradox: “Where is everybody?”. The ultimate aim of this theory is to give a solution using only the facts we can see and evaluate, finding a logical path that could give a full solution, and to raise awareness to the notion that we have of technological developement. 1 INTRODUCTION “Where is everybody?” a deceptively simple question gave birth to one of the most mesmerizing and challenging trouble of the physics and humanity. The cryptic essence and lack amount of information known to us, render this paradox extremely flexible and open to lots of different solutions. Several theories have been made trying to solve this existential enigma. Thereby, what makes this theory different from others? In my humble opinion, the key to understanding and solving the Fermi paradox, is in the definition of the Great Filter[1] itself.Through that we could build a hypothesis regarding our – percieved – loneliness, and defining what life is we could conceive what may cause the arrival of the Great Filter. Explaining the underlying reason to the preparation of the civilization to its collapse, since their birth, we could explain the reason why we have no contact with the extra-terrestrials and why it is impossible to assume the non-existance of other species in the Universe.
    [Show full text]